A power steering system generally utilizes pressurized fluid from a power steering pump to provide an assist in turning a pair of dirigible wheels. In such a system a rotary valve cooperates with an input shaft to communicate the pressurized fluid from the power steering pump to a power cylinder. Depending on the direction of turning, pressurized fluid is communicated to one side of a piston within the power cylinder. With the piston coupled to an output shaft, or steering linkage, movement of the piston by the pressurized fluid imparts movement to the output shaft to provide a power assist upon movement of the input shaft.
As illustrated in U.S. Pat. Nos. 3,602,225 and 3,944,015, the power cylinder and piston take up substantial space and require complex coupling to the output shaft or to the steering linkage. Consequently, a simple rotary actuator, in conjunction with a power steering valve, which is also integrally formed with an output member is believed to be an improvement over the state of the art.